Fibromyalgia (FM) is a chronic painful syndrome characterized by widespread aching and points of tenderness, changed perception of pain and reduced brain serotonin. Abnormal EEG patterns have been reported in this condition. A study of FM occurrence in subjects with sleep abnormalities demonstrated by polysomnography was performed. Fifty patients (group 1:29 with sleep apnea and group 2:21 with poor sleep without sleep apnea) and 31 control subjects (without any sleep abnormalities) were submitted to the same clinical research of FM (ACR criteria). There was one 1 FM in group 1 (3.4%), one FM in group 2 (4.7%), and one FM in control group (3.2%). Sleep abnormalities and particularly sleep apnea are not significantly associated with FM. Other pathophysiological factors than central mechanisms are probably involved in the pathogenesis of FM.